Throw-outs for automatic clamp-lifters



Jan. 10,1956 M. M CANN 2,730,058

THROW-OUTS FOR AUTOMATIC CLAMP-LIFTERS Filed April 16, 1953 I 2 Sheets-Sheet l IN VEN TDR.

77111039 BY Miahuel 1% 61mm;

ATTORNEY Jan. 10, 1956 M, MCCANN 2,730,058

THROW-OUTS FOR AUTOMATIC CLAMP-LIFTERS Filed April 16. 1953 2 Sheets-Sheet 2 INVENTOR. Michael lwoliann WITNESS y ATTOENEY United States Patent 2,730,058 THROW-OUTS FOR AUTOMATIC CLAMP-LIFTERS Michael McCann, Union, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. 1., a camerafion of New Jersey Application April 16, 1953, Serial No. 349,281

3 Claims. (Cl. 112-110) This invention relates to work-clamp lifting devices for cyclically operated article-attaching sewing machines, and more particularly, to a throw-out mechanism by which an automatic work-clamp lifting mechanism may be rendered either operative or inoperative at the will of the sewing machine operator.

The present invention is especially adapted for use with an automatic clamp-lifting mechanism, such as is disclosed in my prior Patent No. 2,300,585, Nov. 3, 1942, in which the upward movement of the needle bar is utilized during the final stitch of the cycle to lift and maintain the upper or article gripping jaw of the workclamp in raised position while the machine is stopped.

In certain applications, this automatic clamp-lifting feature is disadvantageous. Primarily, this stems from the fact that, in addition to lifting automatically, the clamp is also closed automatically; and the cycle of operation, once started, cannot be stopped short of completion. In the event that the work-fabric is improperly positioned, or that the article to be attached is not located properlywith respect to the fabric, there is no opportunity to reposition the work when an automatic clamp lifter is employed. In order to correct any such defect, the stitching must be subsequently removed and the operation repeated. With certain types of work, Where accuracy of location of the attached article is important, many machine operators prefer to discontinue operation of the automatic clamp lifter. Again when an operator must begin a particular article attaching job of which she is unaccustomed, it may be desirable that the automatic clamp lifter be rendered inoperative until such time as the operator gains sufficient proficiency at that specific job to make the use of an automatic lifter worthwhile.

It is an object of thisjinvention to provide an economical and efficient throw-out device for an automatic clamp lifter.

It is a further object to provide a throw-out device of the above character which may be applied to existing machines by a mere substitution of a sub-assembly, thus eliminating a major installation cost item which is inherent in existing and more complicated throw-out constructions.

With these and other objects and advantages in view invention.

Fig. 3 is a top plan view of the throw-out connection including a fragment of each of the clamp-lifting pushrods.

2,730,058 Patented Jan. 10, 1956 Fig. 4 is an exploded perspective view of the clamp lifting throw-out connection of Fig. 3.

Fig. 5 is a perspective view of a modified form of the throw-out sleeve member.

In the preferred embodiment, the invention is illustrated as applied to a button sewing machine equipped with an automatic clamp-lifting mechanism which is constructed substantially in accordance with my prior Patent No. 2,300,585. Since, however, the present invention has application in a variety of other article attaching sewing machines, and with other types of clamp lifters, a general description of these parts will be sufficient for an understanding of the instant invention, reference being made to the above patent for a more detailed description of the sewing machine and automatic clamp-lifting mechanism.

As illustrated in Fig. 1, the sewing machine comprises a frame including a bed 10, a vertical standard 11 and a bracket-arm 12 extending from the standard and terminating in a hollow sewing head 13. Journaled lengthwise in the bracket-arm is a main-shaft M which extends into the sewing head and is there provided with a needlebar driving crank 15. A needle 16 is carried by a needlebar 17 which is journaled for vertical reciprocation in hearings in the sewing head. Secured to the needle-bar is a collar 18 to which is pivoted one end of a link connection 19 with the crank 15. Cooperating with the needle in the formation of chain stitches is a rotary. looper 29 journaled in the bed and driven from the main shaft by suitable connections therewith (not shown).

Journaled on a stud-shaft 22 disposed transversely of the machine standard 11 is a cam-disk 2?: which is driven at reduced speed from the main shaft by means of a worm 24 and a worm-wheel 25. The primary purpose of the cam-disk 23 is to provide motion necessary to shift the work between stitches to effect the desired pattern of stitches or tack as it is called. Movements of the work are derived from two separte cam-grooves, each located on opposite sides of the cam-disk, one such cam-groove being illustrated at 26. The movement imparted by each cam-groove is transmitted by a separate follower linkage, of which one is indicated generally as 27, to a work-clamp 28 which is slidingly pivoted with respect to the bed it The illustrated cam-groove 26 and follower linkage 27 serve to oscillate the work-clamp laterally across the bed 10 and thereby to produce stitches between a first pair of holes in a button. A second carngroove and follower linkage which is not illustrated serves in the usual manner to shift the work-clamp lengthwise of the bed so as to locate a second pair of holes of the button in position to receive stitches on continued oscillation of the work-clamp.

The camdisk 23 also serves to control the cyclic opera tion of the machine by means of a stop-motion device which is indicated generally as 30. One or more cam lugs 31-31 which project from the cam-disk 23 may be rendered effective to trip a latch lever 3.2 associated with the stop motion device, thereby, in a weli known manner, bringing the machine to a stopped position in which the needle-bar 17" is raised. By means of a starting lever 3.3 which is provided with a chain 34 for a treadle or knee shifter connection, the machine may be started, after which the machine will operate until one of the cam lugs 31-491 again trips the stop motion latch lever.

A general description will now be made of the flat button work-clamp illustrated in Fig. l as well as the automatic clamp-fitting mechanism which is described in greater detail in my prior Patent No. 2,300,58

The work-clamp 28 comprises a lower fabric supporting jaw 40 which is slidably pivoted on the bed 11 and operatively connected to the clamp shifting linkages. An

upper article gripping-jaw 41 is pivotally secured to the low r j .40. fon vement yertica w threspe t ql lower jaw to open and close the clamp jaws. Fig. 1 illustrates the usual flat button-gripping upper jaw in which opposed fingers 42-42 are arrangedyieldingly to grip a pin 66 carried by a collar 67 fast on-the'upper extremity of the clamp-lifting bar 45. At its opposite extremity, the

fiat button. A leaf spring 43 is provided. which normally tillyarranged on the clamp-lifting bar and formed to straddle the guide, 46" is an abutment member '47 which is provided at one side with a horizontally extending abutmentfinger 48. When the abutment member is turned so that .thelfinger 48 overliesand is engaged by the collar 18 on the needle-bar during the upstroke of the latter, the needle-bar iseffectively harnessed so as to carry upwardly with itthe clamp-lifting bar 46, the arm 45, the upstanding book 44, and consequently, the upper jaw 41 of the work-clamp, thus opening the clamp as the needle reaches the. top of its stroke.

In the present invention, a two part push-rod, including a head-end portion 50 and a standard-end portion 51, is utilized to control the angular position of the abutment member 47. The head end portion 50 of the push-rod extends through a clearance aperture 52 in the sewing head, and its apertured transversely at 53 to receive a vertical pin 54 carried by the abutment member 47. The

-- abutment member is normally biased in aclockwise direction, when viewed in plan, on the clamp-lifting rod 46 to a position in which the finger 48 is out of the range of movement of the collar 18 on the needle-bar. by means of a coil-spring 55 which is disposed about the head-end portion 50 of the push-rod and which spring is confined in compression between the sewing head and a plunger member 71 which is fast on the head end portion 50 of the push-rod as will be described later. The standard end portion 51 of the push-rod is journaled in a bearing bracket 57 which is carried by the machine frame and disposed adajacent the periphery of the'cam disk 23.

A manually adjustable connection, indicated generally as 60, is provided between the push-rod portions 50 and 51, whereby the overall length of the push-rod'may be changed at the will of the sewing machine operator to either a predetermined shortened or to an extended position, When in extended position, as'illustrated in Figs. 1 and 2, thefree end of the standard-end portion 51 of the push-rod is disposed in the path of one or more camlugs 61-61 carried by the rim of the cam-disk 23. The

push-rod is thus in position to be engaged and shifted axially by one of the cam-lugs 61-61 in opposition to the coil spring 55 and thus to turn abutment finger 48 in a counterclockwise direction into a position where it overlies the collar 18 on the needle-bar. The cam lugs 61-61 are arranged on the cam disk 23 in such angular relationship with the stop motion cam-lugs 31-31 that the operation of the automatic clamp-lifting mechanism will be timed to occur during the final upstroke of the needle at the conclusion of the stitching cycle.

When the length of the push-rod is shortened by circular adjustment of the connection 60, the free end of the push-rod is withdrawn toward the standard and out of the path of the cam-lugs 61-61 and the automatic clamp-lifting -mechanism is, consequently, rendered inoperative.

With this adjustment of parts, themachine proceeds into stopped position with the clamp in lowered work'gripping relation, andthe clamp must be opened-manually, as for instance, by means of a clamp-lifting lever 62 fulcrumed at 63 to a bracket ,64 carried by the bracket-arm of the sewing machine}; The clamp-lifting lever .62 is provided at one extremity withbifurcations' 65-65 which embrace a lever 62 is provided with a treadle or knee shifter connection 68.

Figs. 3 and 4 best illustrate the preferred form of throw-out connection 60 between end portions 50 and 1 of the push-rod by which the automatic clamp-lifting mechanism may be rendered either operative or inoperative at the will of the sewing machine-operator. The adjustable connection comprises a sleeve member 70 and a plunger member 71 which is telescopically arranged within the sleeve. The sleeve member 70 is provided at one extremity with a tapped bore 72 to accommodate the threaded extremity of thestandard end portion 51- of the push-rod. 'A lock nut 73 is provided to secure the threaded connection against accidental loosening, and both the sleeve 70 and the push-rod portion 51 are provided with hexagonal wrench accommodating surfaces 74 and 75, respectively, so as tofacilitate initial adjustmentv ofv the length of the push-rod; At the opposite extremity, the sleeve member 70- is counterbored, as at 76, to. ac-

Theplunger 7 member 71 is provided with an axial bore 771adapted to accommodate the head-end portion 50 of thepush-rod.

The plunger member is also drilled and tapped radially, as at 78, to accommodate a set screw 79 by whichthe push-rod portion 50. is secured in the bore 77. The set screw 79 serves an additional purpose as a cam pin of the throw-out connection as will now be described.

The counterbored portion of the-sleeve member 70 is slotted-toslidablyaccommodate the shank of the set screw 79. ;In the embodiment illustrated-in Figs. 1 through 4, the extremities 82 and 83 of the slot are offset axially and are connected by a spiral portion 84 of the slot.

The side walls of the slot extremities 82 and 83 provide-abutment surfaces with which thesetscrew 79 may be selectively engaged simply by turning .the sleeve member 70. Since the abutment surfacesare spaced axially of the sleeve member .70, turning of the sleeve to shift the set screw 79 from one to the other of the slot extremities serves to alter the overalllength of the push-rod. When the set screw shank is disposed in the slot extremity 82, as shown in Figs. 1, 2 and 3, the

' push-rod is; lengthened and arranged in operative posiformed by the legs 87 and 88. faces thefree extremity of the sleeve member while the legs 87 and 88 ,eachextend a different distance from the apex and toward the stand ard end of the machine. The extremities of each ofthe leg portions 87 and 88, provide abutment surfaces for selective engagement with the shank of the set screw 79. Sincethe abutment surfaces are .spaced axiallyv ofthe sleeve member 70, turningof the sleeve member to shift the set screw from one tothe other of the abutment surfaces will alter the effective length'of the push-rod-to throw the. clamp-lifting mechanism into or out of operation at the will of the sewing machine operator. 1

. Having thus set forth the nature of the invention, what I claim herein is:

1. In a cyclically operated sewing machine having-an actuating mechanism, a work-clamp, and automatic workclamp opening mechanism of thetypeincluding a member shiftable into and out of driven' relation with said actuating mechanism, cam means driven fromsaid actushiftable member and said cam means, said push'rodcomprising two axially opposed end portions adjustable axially one with respect to the other, an angularly adjustable sleeve member fixed axially with respect to a first of said axially opposed push rod portions and telescopically arranged with respect to the second of said push rod portions, a radially extending pin carried by said second push rod portion, said sleeve member formed with a slot of which each extremity extends at an angle of not more than 90 with respect to the first push rod portion, said slot extremities defining two pin-accommodating abut ment surfaces spaced apart both angularly and axially of said second push rod end portion.

2. A device as claimed in claim 1 in which said sleeve member is formed with a pin accommodating slot having a central portion of substantially spiral contour, said slot being formed at each extremity with spaced slot defining walls disposed each in a plane perpendicular to the axis of said push rod to provide pin-accommodating abutment surfaces spaced apart both angularly and axially of said second push rod end portion.

3. A device as claimed in claim 1 in which said sleeve member is formed with an L-shaped pin-accommodating slot having legs of different length extending each at an acute angle with respect to the first push rod portion and terminating in pin-accommodating abutment surfaces disposed in spaced relation axially of said second push rod end portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,201,274 Singer May 21, 1940 2,517,700 Odin Aug. 8, 1950 2,540,987 McCann Feb. 6, 1951 2,579,635 Weiss Dec. 25, 1951 

